Current minimum smoke rocket motor solid propellants produce fuel rich exhaust products that combust or afterburn with air beyond the nozzle exit of the rocket motor. Such afterburning does not contribute to rocket motor thrust, is undesirable, and in many cases is unacceptable because it increases the radiation emission signature of the missile.
There are many documented approaches for the use of chemical means to suppress afterburning, however they have not been proven to be acceptable for accomplishing the desired results in afterburning. Depending upon the nature of the chemicals used, various previous methods have included: (1) the incorporation of the chemical suppressant into the main rocket motor propellant itself, (2) coating resonance rods with the chemical suppressants and placing them inside the rocket motor structure and (3) using ablative nozzle rings or sections in the rocket motor for providing suporessant for the rocket motor.
Many solid propellants that are used in these minimum smoke type solid propellants are chemically or otherwise incompatible with the suppressant so that direct incorporation into the minimum smoke solid propellant is not possible. In these prior devices, the ablative technique is ineffective and requires large amounts of suppressant that results in smoke signature. Therefore, it can be seen that a device or technique that is effective in eliminating or effectively controlling afterburning in a rocket motor is badly needed.
Accordingly, it is an object of this invention to provide a new device and technique for introducing chemical flash suppressants into a rocket motor through an igniter assembly for the main propellant of the rocket motor.
Another object of this invention is to provide an igniter for a solid propellant such that the igniter is designed to provide suppressant material that is ablated as a coating in a controlled fashion during sustained igniter burning.
Still another object of this invention is to provide a device which utilizes a technique of injecting material into a rocket motor cavity by means of a pyrogen igniter which has a controlled burning grain for injecting the material into the motor cavity as the pyrogen igniter burns.
A still further obiect of this invention is to provide arrangements of grain or pellet design for an igniter which incorporates both suppressant and pyrotechnics into each igniter gain or pellet for controlled introduction of suppressant into a rocket motor chamber that has a smokeless solid propellant burning therein.
Other objects and advantages of this invention will be obvious to those skilled in this art.